PSS Shaft Seal Shaft Size – 1.500″ Stern Tube Diameter – 2.250″- 2.375″ – 02-112-214. As with any rubber hose below waterline, the PSS bellows must be inspected on a regular basis for any sign of wear, aging or chemical deterioration. PYI suggests preventative maintenance. The PSS bellow should be replaced in six year intervals. During bellows replacement it is recommended the o-rings & set screws in the stainless steel rotor also be replaced.
Bellows may need to be more frequently inspected in an environment where non-sealed batteries emit sulfuric acid. Sulfuric acid vapor will accelerate rubber deterioration, as will an ozonater.
NEVER USE SET SCREWS MORE THAN ONCE!
Please be sure to never use the same set screw on the shaft twice. There are two set screws in each of the two holes in the stainless steel rotor. One is tightened onto the shaft and the other is tightened onto the first to lock it in place against the shaft. The set screws are made with a cup at the base that compresses into the shaft ensuring a secure grip. PYI’s PSS Maintenance Kit comes with five new set screws included. When re-installing the rotor please use new set screws. In the case that you do not have spare set screws, the set screws in the rotor need to be reversed so there is an unused cup being compressed onto the shaft.
PYI offers a Maintenance Kit that includes the items you need to properly maintain your PSS Shaft Seal. Included in the kit is:
- 1 Bellow
- 2 o-rings
- 5 Set screws
- 4 Hose clamps
- 1 Tube of thread lock
- 1 Allen key
The PSS Shaft Seal is the #1 selling marine mechanical seal worldwide and is installed as standard equipment by many of the worlds most reputable boat builders and boat yards. The PSS Shaft Seal is also recognized as the premiere retrofit (aftermarket) seal on the world market. Boat builders and boat yards recognize the advantages and value of installing the PSS as it eliminates the maintenance, constant adjustment & cost associated with traditional packing type glands. Aside from these benefits, the PSS Shaft Seal helps to eliminate water in the bilge (100% water tight) & wear to the propeller shaft.
The Type A PSS Shaft Seal is a mechanical face seal. The sealing surface is created between the flat surfaces of the rotating stainless-steel rotor and the stationary carbon flange. The stationary carbon flange is attached to the front side of the bellow with hose clamps, and the back end of the bellow fits over the Stern tube and is secured with hose clamps. The stainless-steel rotor is fit on the shaft in front of the carbon flange. The stainless-steel rotor is used to compress the bellow before the rotor is secured to the shaft with set-screws. This compression (pre-load) maintains constant contact between the two flat faces of the stainless-steel rotor and carbon flange, allowing the PSS to compensate for the variable fore and aft movement due to propeller thrust. The carbon flange is over-bored to the shaft diameter allowing it to “float” around the shaft and thus compensate for most misalignment and vibration problems. The stainless-steel rotor is sealed to the shaft by two O-rings that are recessed into the bore of the collar. These O-rings rotate with the shaft and stainless-steel rotor and do not experience wear during operation.
- Temperature Limits: 5 degree F to 225 degree F (-15 degree C to 107 degree C)
- Pressure Limits: 15 PSI (1 BAR)
- Shaft RPM Limits: 10,000 RPM
- Carbon Graphite: Lapped to 4 HLB (0.000044″ tolerance)
- 316SS / Nitronic 50: Faced to 9 Ra
- Bellow Material: Molded Nitrile – PVC